Dave Mehlman, the director of The Nature Conservancy’s migratory bird program, is blogging all week about the new “State of the Birds 2010″ report, of which he is a co-author. Read all his posts on the report — then go to my.nature.org to learn more about the report and the Conservancy’s work to protect birds.

There is an almost irresistible tendency when discussing the effects of climate change on birds (as illustrated by the State of the Birds report) to portray the results as inevitably bad. Indeed, our analyses of bird species vulnerability to climate change does suggest that many species show elevated vulnerability to climate change.

However, the great difference between birds from different habitat types in their vulnerability suggests that there are indeed some species who will do just fine in the face of climate change, including some who may well prosper. In addition, some conservation efforts are already underway to help birds adapt to a changing climate, providing yet another element of good news.

The relatively low proportion of bird species occurring in forests suggests that, due to their high reproductive potential and large ranges, many forest birds will fare better in the future (though we may see some species that become rarer in the United States but more common in Canada).

There are numerous examples of birds that are now of relatively restricted range in the United States but are currently expanding dramatically, such as Cactus Wren, Cave Swallow and White-winged Dove. Similarly, species now rare in United States but found commonly in Mexico may move northward and become more common in our country, including Northern Beardless-Tyrannulet, Bronzed Cowbird and Crested Caracara.

Perhaps the best news is that conservation efforts are already underway that will help birds in the face of climate change. For instance:

• Planners and refuge designers across the country are aware of the changes that are coming and can incorporate this knowledge into their work — for example, by developing altitudinal or elevational corridors connecting protected areas.
• Recent efforts at translocating individuals from one place to another, such as those implemented for the Bermuda Petrel, offer great hope for ensuring the survival of rare species, albeit in a relatively expensive manner.
• The Nature Conservancy has been actively partnering with the U.S. Fish and Wildlife Service at the Alligator River National Wildlife Refuge, North Carolina, in an innovative project to protect coastal marshes by plugging ditches to limit saltwater intrusion, planting salt tolerant species, and building oyster reefs for shoreline protection.

Climate change presents a strong challenge to most of our nation’s birds, exacerbating the largely negative trends we showed in the 2009 State of the Birds report. However, not all species will be affected equally –and some perhaps many species will benefit in some form. There are promising strategies for helping species adapt to a changing climate and these efforts must be expanded, coupled with a rigorous monitoring scheme to determine their effectiveness. Although the picture appears dark for birds overall regarding climate change, there are some lights in the darkness which may help guide our way.

(Image: Cactus wren. Image credit: SearchNetMedia/Flickr through a Creative Commons license.)

Opinions expressed here and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy. For more information about our editorial policy and legal terms of use, see our About This Blog page.

Dave Mehlman, the director of The Nature Conservancy’s migratory bird program, is blogging all week about the new “State of the Birds 2010″ report, of which he is a co-author. Read all his posts on the report — then go to my.nature.org to learn more about the report and the Conservancy’s work to protect birds.

The 2010 State of the Birds report focuses on birds and climate change — and found that birds of the three primary terrestrial habitat types (aridlands, grasslands, forests) showed relatively the least vulnerability to global warming.

However, each of these habitat types contains species that are dramatically more vulnerable to climate change. Even more notable, most of these species are not currently considered of conservation concern, suggesting that future attention will be warranted if action is not taken now.

Aridlands and grasslands share similar predicted effects of climate change: They will become warmer and drier. In aridlands, we also expect the already variable precipitation regime to become yet more variable, with longer and harder droughts and infrequent spells of heavy precipitation.

Aridlands are also at risk of increased invasion by non-native species of plants which could have major negative effects on our native avifauna. Examples of vulnerable aridlands species are found across the country, including Greater and Gunnison Sage-Grouse of the Colorado Plateau and Great Basin, Bendire’s and Crissal Thrasher of the Chihuahuan Desert, Black-capped Vireo of the Edwards Plateau, and Wrentit of the coastal California chaparral.

Grasslands are at great risk of invasion by woody species — both native and introduced — that can irretrievably alter these systems and affect the birds that rely on them. Although some grassland species, such as Loggerhead Shrike and Northern Bobwhite, are tolerant of some degree of woody plant cover, many other species of grassland birds, such as Chestnut-collared Longspur, will disappear with even a slight increase in woody shrubs. Other grasslands species particularly vulnerable to climate change include resident birds such as the Sharp-tailed Grouse and Greater and Lesser Prairie-Chicken and long distance migrants such as Wilson’s Phalarope, Dickcissel, and Bobolink.

Although birds of forests show relatively the least vulnerability to climate change of all habitats we analyzed, we nevertheless expect change to occur. Northward shifts in tree species’ ranges, increases in the frequency of insect outbreaks, longer and more severe fire seasons, and generally drier conditions will all result in changed bird species distributions.

Some of the most vulnerable forest species include those restricted to isolated, small habitat types in either the breeding or wintering season, such as Kirtland’s Warbler or Bicknell’s Thrush.  Of most concern, however, are a group of species known as “aerial insectivores”, such as Black Swift, Whip-poor-will, and Chuck-will’s-widow, which, in addition to the factors listed above, are at risk from declines in their medium and large-bodied insect prey.

(Image: Bobolink, Chester County, Pennsylvania. Image credit: kellycolganazar/Flickr through a Creative Commons license.)

Opinions expressed here and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy. For more information about our editorial policy and legal terms of use, see our About This Blog page.

Dave Mehlman, the director of The Nature Conservancy’s migratory bird program, is blogging all week about the new “State of the Birds 2010″ report, of which he is a co-author. Read all his posts on the report — then go to my.nature.org to learn more about the report and the Conservancy’s work to protect birds.

The 2010 State of the Birds report focuses on birds and climate change, and shows that birds of Arctic and Alpine habitats are some of the most vulnerable in the country to climate change.

Documented temperature increases in the Arctic are already greater than in other regions — and we expect equally dramatic changes in the distribution of surface-water vegetation and food resources. Given that Alpine habitats are inherently insular in nature, we expect many of the effects of climate change on islands to be duplicated in Alpine areas, including the total loss of these habitats at lower elevations and latitudes.

Species affected by these changes including many of our long-distance migrating shorebirds and waterfowl, plus species restricted to the highest elevation habitats of the interior mountains. These include Surfbird and Black Turnstone, which breed on the Arctic tundra, and Brown-capped Rosy-Finch of the Rocky Mountains.

Melting permafrost may release contaminants into the environment, adding new threats to those faced by Spectacled Eider, Yellow-billed Loon, and Sabine’s Gull.  Changes in the abundance and distribution of small mammals could lead to decreases in Snowy Owls and jaegers or an increase in their reliance on birds and other prey.

Although wetlands birds in general show relatively lower vulnerability to climate change compared to other habitat types, it is clear that even small changes in precipitation and temperature can degrade or eliminate wetlands over broad areas. This is especially true of the shallow wetlands of the Prairie Potholes, Americas “duck factory.”  Examples of species particularly vulnerable include Western and Clark’s Grebes, Northern Pintail, and Black and Clapper Rails.

(Image: Snowy owl against snow in Alberta, Canada. Image credit: BugMan50/Flickr through a Creative Commons license.)

Opinions expressed here and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy. For more information about our editorial policy and legal terms of use, see our About This Blog page.